September 07, 2008

Barry C. Smith on Neuroscience

In this interview for Philosophy BitesBarry C. Smith, the new director of the Institute of Philosophy in London, discusses the impact of recent discoveries in neuroscience (including blind sight and mirror neurones) on our understanding of the mind and our senses.

Comments

Blind-sight: the world-wide extent of the practice of trephination in ancient times reveals how much our ancestors reasoned that something strange was happening in the heads of certain individuals. Blows to the head during conflict situations would presumably have been more common than today, and congenital brain damage must also have arisen. The intriguing question is how the fellows of the victim would have reacted if they discovered that a certain proportion of such people were later able to demonstrate blindsight. Would this have been a sign that trephination was a cause or a requirement, or a sign that the individual was somehow blessed? All three are possible, so the wisdom of the local elder or seer would presumably have prevailed and beliefs would likely have become set in place according to what was observed. Intent and belief seem closely allied, as are assumptions as to their ancient portents.

My point is that neuroscience is providing us a new lens with which to re-evaluate our assumptions about our past. In the past and the present, I also ask myself whether the combinations of shamanist or modern illicit substances which yield some form of oracular sight are linked to similar neural mechanisms. Today, we (largely) suspect that oracular sight is a purely internal phenomenon, but historically we can see that decisions on warfare, inheritance, marriage, politics, alliances and so on were sometimes made on the basis of information deduced whilst under drug influence. There are too many examples to list, but the wealth accumulated by e.g. the Delphic oracle suggests considerable patronage and therefore presumptions as to reliability (recognising that such oracles also had extensive ‘manual internets’ of information feeds from the courts and couriers of the payers and payee - allowing the fine tuning of assumptions as to how future events would affect the intent of key individuals).

The value of unconscious seeing would also appear to relate to our ability (or inability) to aim at and spear a moving prey animal. If you have tried archery, it often seems easier to hit the target if you don’t force yourself to focus on it quite so hard. Were some ‘gatherers’ the individuals who were less able to throw spears, etc, with regular success? This situation has always struck me as one where a hidden genetic variable might be in play - the basis of an individual’s ability to aim and fire a device at a moving target. However, hitting a moving target also requires a level of confidence in predicting the intent of its run - will it veer to one side or run in a straight line? This seems to be where mirror neurones come into play.

Mirror neurones: Genetic variation would likely also apply here too, but at several levels. The population of mirror neurones in a brain may vary, but so too might their ‘colours’ or ‘flavours’. The value in the ability to deduce an intent seems to be an advantage as a practical (and perhaps survival) skill as well as the basis for intuition or a level of educational ability. Might it be the case that natural variations in the mirror neurone population of a brain are linked to an individual’s ability to progress beyond a certain level of education? As we look across the population of children and their ability or apparent inclination to learn, we seem to make assumptions that all have equal potential - yet annual statistics of reading ability suggest such assumptions may be unreasonable. So-called ‘intelligence’ chemicals like omega vitamins might perhaps provide the raw materials for the more successful development of the mirror neurone network, but the evidence is patchy.

However, the more intriguing implications of the ability to deduce intent arise from the fact that the ability is not simply present at the visual-image level. We also deduce intent from the word-pictures in literature. For example, we understand the described characteristics that comprise murderous intent and its motivations as articulated by writers in the crime-thriller genre. Some readers are plainly better than others at spotting the murderer (by way of their deduced motivations for intent) well in advance of the denouement. We also understand the reported intent of a god and a God to be quite different - just the capitalisation changes our perception of significance. The implied images in hieroglyphs and pictograms can also convey intent, but the ancients may have read more into them than we might today. Modern icons are no less loaded with intent however, and the power of brands over our collective consciousness is quite palpable.

We gauge the intent of a person’s look in a photograph, but likewise when regarding a character depicted in a work of art. Some people are better than others, and some mis-read intent more frequently (even to a degree of paranoia perhaps). Similarly, we can listen to a symphony and hear intent in the form of cues that signal that the music is about to jump from a placid but slowing tempo to a moment of attack (first movement of Tchaikovsky’s 6th, for example) - even in a situation when we have never heard the work before. The same applies to popular music tracks as well, allowing the anticipation of a change in dance rhythm or transition to a new key or harmony.

In the ancient situation, the ability to deduce the intent of an animal or human according to the nature of their heard-only footsteps in the night would have been a survival ability. But the nature of the ability to deduce intent becomes more extraordinary when looking at a painting by someone like Van Gogh. Our ability to read the brush-strokes as a clue to the mental state of the artist and his intent in applying them to the canvas in a certain way suggests an extraordinary sensitivity in the ability to interpret the available information. This, and the fact that some viewers cannot perceive such detail at all (or see any useful value in art or classical music) suggests a genetic variance in the mirror neurone architecture and related chemistry. It also raises questions as to whether such variances may be compensated for by ingestion of medicines or the application of gene therapies.

Fascinating, but there are subtleties here as well: Musicians (and car-drivers) can deduce the intent of their fellows by means of visual and aural cues. A player can subconsciously correct, moment by moment, for being faintly off key or off beat. A musician can also adjust their own playing if they hear a better communication of emotional-tonal intent emanating from a nearby colleague (as well as from a conductor or fellow artist’s direction). A valuer of antiques can also deduce the likely level of aquisitional intent in an auction room such that a selling price for an object can be predicted in advance. Knowledge - assumptions based on the analysis of previous patterns of information - plays a part, but it would appear that it is the mirror neurone system that adds a greater value. What, then, is different about the mirror neurones of a musician or art-appreciator, or anyone who is more clearly more sensitive to emotional cues than most other individuals?

Lastly, many dog owners will have observed how their dog is able to deduce the owner’s intent according to visual information, vocalisations or tugs on a lead. It does not take much reflection to recognise how common the feature is in mammals generally, and to a more variable extent in other species. Some species read any movement as demanding of immediate flight, but others are much more specific about their response to particular types of movement. Some are clearly automated responses, and some are subject to varying levels of choice. Evolution would appear to favour the latter, and humans appear to exhibit a point of handover during their adolescence from a more automated state to one of more extensive voluntary control over both choice per se and choice of intent (and choice as to whether to broadcast or mask that intent). For some individuals this is entirely intuitive, but for others it is not - even with training. Intelligence may not be genetic, but mechanisms that facilitate it may well be.